There are two systems of Periods which are prevalent in India. Vimshottari Dash and Ashtottari Dasha - the former in North India and the latter in South India. Complete Vimshottari Dasha cycle consists of 120 years, whereas Ashtottari Dasha is of 108 years. Some sages have opined that persons born during the Bright Half of Moon (between New Moon and the Full Moon) should follow Vimshottari Dasha, whereas persons born in the Dark Half of Moon (between the Full Moon and New Moon) should follow Ashtottari Dasha. On the other hand, some sages have opined that persons born in North should follow Vimshottari Dasha and persons born in South should follow Ashtottari Dasha. However, most of the eminent astrologers, saints and rishis held that Vimshottari Dasha holds good in all the cases.

Horoscope tells us about general effects of the planets - good or bad. But one important question remains unattended : When? The timing of an event? That is, when will a particular event happen? When will the good period start? When will the bad period end? Here we take the help of Period System - Vimshottari Dasha. For example, we want to know when one will get more profits. We know XIth house is House of Profits. Find out its Lord, and then see when its Major Period or Period will be there. That period will give him more profits.

Calculation of Vimshottari Dasha

There are 27 stars/nakshatras (already explained). They are grouped into triads and each group is ruled by a particular planet. Moon at the time of birth will be passing through one of these stars. That star is the birth star and Vimshottari Dasha will start from the Lord of that birth star. The triads of stars, their lords and their periods are given below:

The periods are always in the order given above. That is, if the first Period is of Mars, next period will be of Rahu, then of Jupiter, Saturn, Mercury, Ketu, Venus, Sun, and Moon. If the first Period is of Ketu, next period will be of Venus, then Sun, Moon, Mars, Rahu, and so on.